In-situ X-ray diffraction (XRD) method has been developed for the observation of elctrodeposition process in molten NaCl-2CsCl salt to investigate the mechanism of pyrochemical process of nuclear fuel reprocessing system. In this paper, the scattered X-ray beam from electrodepositing nickel in NaCl-2CsCl melt was measured by the reflection mode at BL19B2 beamline of SPring-8 as the preliminary experiment. The time dependence of the electrodepositing nickel in NaCl-2CsCl melt at 923K was investigated by the in-situ XRD measurements.